| 摘要 |
A method and drilling apparatus to make a hole or tunnel in different types of soil, such as rock or clay, using one and the same drill bit or a bit assembly (2, 3), (9, 10). By means of the conical design of the bit soft soil is forced to the sides of the hole that is being drilled and, by means of drilling elements (5) on the front face of the bit, encountered stones, rock etc. are crushed into drill waste removable mainly through the bit backward.
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